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Influenza virus: The deadly 1918 pandemic could be the cause of today’s milder seasonal flu

Viruses sequenced from 100-year-old lung samples at museums in Germany and Austria reveal how influenza changes over time.


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May 10, 2022

H1N11918 Influenza virus particles

CDC / SCIENCE PHOTO LIBRARY

Today’s seasonal influenza infections can be caused by the direct offspring of the virus behind the 1918 influenza pandemic.

The pandemic was the most deadly disease outbreak of the last century, infecting one-third of the world’s population. Up to 100 million people died..For comparison, the current covid-19 pandemic is believed to have resulted. 15 million people died By the end of last year.

Much remains a mystery about the 1918 pathogen. Scientists have only shown that the flu was caused by the virus in the 1930s, with few pandemic virus samples left.Some of what we have come to Corpses buried in Alaska’s permafrost, which remained frozen until it was dug up in the 1990s..

Now more light Thorsten Wolff Robert Koch Institute and his colleagues in Berlin, Germany. The team sequenced the virus from 13 lung samples from people who died of lung infections between 1901 and 1931, stored in museums in Berlin and Vienna, Austria. Three of the samples were from people who died in 1918, and two of these samples were collected before the pandemic peak in the last few months of 1918.

Virus from 1918 sample Modern seasonal influenza virusWolff’s team discovered that the modern virus could be a descendant of the 1918 virus.

Researchers also sequenced two samples of the virus from the first few months of the 1918 pandemic before infecting people in the second half of 1918, when the pandemic peaked. Compared to a pandemic virus. They found that there were changes in the genes that encode the nucleoprotein, the protein that surrounds the genetic material of the virus.

Previous studies on cells suggest that these mutations may help avoid the virus. Protection of the human immune system caused by a chemical called interferon, Targets nuclear proteins. This suggests that the virus has evolved to better evade the immune system, Wolff says. “We know this was a really toxic virus,” he says.

For some decade after the 1918 pandemic, influenza deaths have dropped significantly. This may be due to increased herd immunity or reduced virus virulence, Wolff says.

Journal reference: Nature Communications, DOI: 10.1038 / s41467-022-29614-9

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Influenza virus: The deadly 1918 pandemic could be the cause of today’s milder seasonal flu

Source link Influenza virus: The deadly 1918 pandemic could be the cause of today’s milder seasonal flu

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